mesh.py

   1 # -*- encoding: utf-8 -*-
   2 #
   3 #
   4 # Copyright (C) 2006-2011 André Wobst <wobsta@users.sourceforge.net>
   5 #
   6 # This file is part of PyX (http://pyx.sourceforge.net/).
   7 #
   8 # PyX is free software; you can redistribute it and/or modify
   9 # it under the terms of the GNU General Public License as published by
  10 # the Free Software Foundation; either version 2 of the License, or
  11 # (at your option) any later version.
  12 #
  13 # PyX is distributed in the hope that it will be useful,
  14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 # GNU General Public License for more details.
  17 #
  18 # You should have received a copy of the GNU General Public License
  19 # along with PyX; if not, write to the Free Software
  20 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  21
  22
  23 # Just a quick'n'dirty ascii art (I'll do a nice PyX plot later on):
  24 #
  25 #
  26 #      node1 *
  27 #            | \
  28 #            |   \  neighbor2
  29 #            |     \
  30 #            |       \
  31 #  neighbor3 |element * node3
  32 #            |       /
  33 #            |     /
  34 #            |   /  neighbor1
  35 #            | /
  36 #      node2 *
  37
  38
  39 import struct, binascii, zlib, os, tempfile
  40 from . import bbox, baseclasses, color, pdfwriter, unit
  41
  42
  43 class node_pt:
  44
  45     def __init__(self, coords_pt, value):
  46         self.coords_pt = coords_pt
  47         self.value = value
  48
  49
  50 class node(node_pt):
  51
  52     def __init__(self, coords, value):
  53         node_pt.__init__(self, [unit.topt(coord) for coord in coords], value)
  54
  55
  56 class element:
  57
  58     def __init__(self, nodes, neighbors=None):
  59         self.nodes = nodes
  60         self.neighbors = neighbors
  61
  62
  63 def coords24bit_pt(coords_pt, min_pt, max_pt):
  64     return struct.pack(">I", int((coords_pt-min_pt)*16777215.0/(max_pt-min_pt)))[1:]
  65
  66
  67 class PDFGenericResource(pdfwriter.PDFobject):
  68
  69     def __init__(self, type, name, content):
  70         pdfwriter.PDFobject.__init__(self, type, name)
  71         self.content = content
  72
  73     def write(self, file, writer, registry):
  74         file.write_bytes(self.content)
  75
  76
  77 class mesh(baseclasses.canvasitem):
  78
  79     def __init__(self, elements, check=1):
  80         self.elements = elements
  81         if check:
  82             colorspacestring = ""
  83             for element in elements:
  84                 if len(element.nodes) != 3:
  85                     raise ValueError("triangular mesh expected")
  86                 try:
  87                     for node in element.nodes:
  88                         if not colorspacestring:
  89                             colorspacestring = node.value.colorspacestring()
  90                         elif node.value.colorspacestring() != colorspacestring:
  91                             raise ValueError("color space mismatch")
  92                 except AttributeError:
  93                     raise ValueError("gray, rgb or cmyk color values expected")
  94                 for node in element.nodes:
  95                     if len(node.coords_pt) != 2:
  96                         raise ValueError("two dimensional coordinates expected")
  97
  98     def bbox(self):
  99         return bbox.bbox_pt(min([node.coords_pt[0] for element in self.elements for node in element.nodes]),
 100                             min([node.coords_pt[1] for element in self.elements for node in element.nodes]),
 101                             max([node.coords_pt[0] for element in self.elements for node in element.nodes]),
 102                             max([node.coords_pt[1] for element in self.elements for node in element.nodes]))
 103
 104     def data(self, bbox):
 105         return b"".join([b"\000" + coords24bit_pt(node.coords_pt[0], bbox.llx_pt, bbox.urx_pt) +
 106                                    coords24bit_pt(node.coords_pt[1], bbox.lly_pt, bbox.ury_pt) +
 107                                    node.value.to8bitbytes()
 108                          for element in self.elements for node in element.nodes])
 109
 110     def processPS(self, file, writer, context, registry, bbox):
 111         if writer.mesh_as_bitmap:
 112             from pyx import bitmap, canvas
 113             from PIL import Image
 114             c = canvas.canvas()
 115             c.insert(self)
 116             i = Image.open(c.pipeGS("pngalpha", resolution=writer.mesh_as_bitmap_resolution))
 117             i.load()
 118             b = bitmap.bitmap_pt(self.bbox().llx_pt, self.bbox().lly_pt, i)
 119             # we slightly shift the bitmap to re-center it, as the bitmap might contain some additional border
 120             # unfortunately we need to construct another bitmap instance for that ...
 121             b = bitmap.bitmap_pt(self.bbox().llx_pt + 0.5*(self.bbox().width_pt()-b.bbox().width_pt()),
 122                                  self.bbox().lly_pt + 0.5*(self.bbox().height_pt()-b.bbox().height_pt()), i)
 123             b.processPS(file, writer, context, registry, bbox)
 124         else:
 125             thisbbox = self.bbox()
 126             bbox += thisbbox
 127             file.write("""<< /ShadingType 4
 128 /ColorSpace %s
 129 /BitsPerCoordinate 24
 130 /BitsPerComponent 8
 131 /BitsPerFlag 8
 132 /Decode [%f %f %f %f %s]
 133 /DataSource currentfile /ASCIIHexDecode filter /FlateDecode filter
 134 >> shfill\n""" % (self.elements[0].nodes[0].value.colorspacestring(),
 135                   thisbbox.llx_pt, thisbbox.urx_pt, thisbbox.lly_pt, thisbbox.ury_pt,
 136                   " ".join(["0 1" for value in self.elements[0].nodes[0].value.to8bitbytes()])))
 137             file.write_bytes(binascii.b2a_hex(zlib.compress(self.data(thisbbox))))
 138             file.write(">\n")
 139
 140     def processPDF(self, file, writer, context, registry, bbox):
 141         if writer.mesh_as_bitmap:
 142             from pyx import bitmap, canvas
 143             from PIL import Image
 144             c = canvas.canvas()
 145             c.insert(self)
 146             i = Image.open(c.pipeGS("pngalpha", resolution=writer.mesh_as_bitmap_resolution))
 147             i.load()
 148             b = bitmap.bitmap_pt(self.bbox().llx_pt, self.bbox().lly_pt, i)
 149             # we slightly shift the bitmap to re-center it, as the bitmap might contain some additional border
 150             # unfortunately we need to construct another bitmap instance for that ...
 151             b = bitmap.bitmap_pt(self.bbox().llx_pt + 0.5*(self.bbox().width_pt()-b.bbox().width_pt()),
 152                                  self.bbox().lly_pt + 0.5*(self.bbox().height_pt()-b.bbox().height_pt()), i)
 153             b.processPDF(file, writer, context, registry, bbox)
 154         else:
 155             thisbbox = self.bbox()
 156             bbox += thisbbox
 157             d = self.data(thisbbox)
 158             if writer.compress:
 159                 filter = "/Filter /FlateDecode\n"
 160                 d = zlib.compress(d)
 161             else:
 162                 filter = ""
 163             name = "shading-%s" % id(self)
 164             shading = PDFGenericResource("shading", name, ("""<<
 165 /ShadingType 4
 166 /ColorSpace %s
 167 /BitsPerCoordinate 24
 168 /BitsPerComponent 8
 169 /BitsPerFlag 8
 170 /Decode [%f %f %f %f %s]
 171 /Length %i
 172 %s>>
 173 stream
 174 """ %            (self.elements[0].nodes[0].value.colorspacestring(),
 175                   thisbbox.llx_pt, thisbbox.urx_pt, thisbbox.lly_pt, thisbbox.ury_pt,
 176                   " ".join(["0 1" for value in self.elements[0].nodes[0].value.to8bitbytes()]),
 177                   len(d), filter)).encode('ascii') + d + b"\nendstream\n")
 178             registry.add(shading)
 179             registry.addresource("Shading", name, shading)
 180             file.write("/%s sh\n" % name)